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A realistic topological p-n junction at the Bi2Se3 （0001） surface based on planar twin boundary defects

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Nano Research 2017年第5期10卷 1784-1793页

作者： Hugo Aramberri m. Carmen munoz Jorge i. Cerda instituto de Ciencia de materiales de madrid (iCmm-CSiC) Cantoblanco Madrid 28049 Spain

We propose a realistic topological p-n junction （TPNJ） by matching two Bi2Se3 （0001） slabs with opposite arrangements of planar twin boundary defects. The atomistic modeling of such a device leads to dislocation defects in the hexagonal lattice in several quintuple layers. Nevertheless, total energy calculations reveal that the interface relaxes, yielding a smooth geometrical transition that preserves the nearest-neighbors fcc-type geometry throughout these defect layers. The electronic, magnetic, and transport properties of the junction have then been calculated at the ab initio level under open boundary conditions, i.e., employing a thin-film geometry that is infinite along the electron transport direction. indeed, a p-n junction is obtained with a built-in potential as large as 350 meV. The calculations further reveal the spin texture across the interface with unprecedented detail. As the main result, we obtain non-negligible transmission probabilities around the F point, which involve an electron spin-flip process while crossing the interface.

关键词： topological insulators p-n junctions spintronics electronic devices twin boundaries

Developing a two-decadal time-record of rice field maps using Landsat-derived multi-index image collections with a random forest classifier:A Google Earth Engine based approach

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information Processing in Agriculture 2024年第2期11卷 260-275页

作者： W.Ashane m.Fernando i.P.Senanayake Department of Nano Science Technology Wayamba University of Sri LankaKuliyapitiya 60200Sri Lanka Dchoolf Engineing CllegeoEngineeringSience and EnionmentThe UniversyewcastleCallaghanW2Austraia

Historic maps showing the temporal distribution of rice fields are important for precision agriculture,irrigation optimisation,forecasting crop yields,land use management and formulating ***,mapping rice felds using traditional ground surveys is impractical when high cost,time and labour requirements are considered,and the availability of such detailed records is *** satellite remote sensing appears to be a viable solution,conventional segmentation and classification methods with spectral bands are often unable to contrast the distinct characteristics between rice fields and other vegetation *** this end,we explored a novel,Google Earth Engine(GEE)based multiindex random forest(RF)classification approach to map rice fields over two *** images from 2000 to 2020 of two Sri Lankan rice cultivation districts were extracted from GEE and a multi-index RF classification algorithm was applied to distinguish the rice *** results showed above 80%accuracy for both training and validation,when compared against high spatial resolution Google Earth *** essence,multi-index sampling and RF together synergised the compelling classifcation accuracy by effectively capturing vegetation,water(ponding)and soil characteristics unique to the rice felds using a single-click *** maps developed in this study were further compared against the mODiS land cover type product(mCD12Q1)and the corresponding superior statistics on rice fields demonstrated the robustness of the proposed *** work seeking effective index combinations is recommended,and this approach can potentially be extended to other crop analyses elsewhere.

关键词： Google Earth Engine(GEE) image classification Random forest mapping rice fields Time series analysis Vegetation index

magnetohydrodynamic approach of non-Newtonian blood flow with magnetic particles in stenosed artery

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Applied mathematics and mechanics(English Edition) 2017年第3期38卷 379-392页

作者： i. A. miRZAt m. ABDULHAmEED S. SHAFiE Abdus Salam School of mathematical Sciences Government College University Lahore 54000 Pakistan School of Science and Technology Federal Polytechnic P. M. B. Bauchi 0231 Nigeria Department of mathematical Sciences Faculty of Science Universiti Teknologi Skudai 81310 Malaysia

The non-Newtonian blood flow, together with magnetic particles in a stenosed artery, is studied using a magneto-hydrodynamic approach. The wall slip condition is also considered. Approximate solutions are obtained in series forms under the assumption that the Womersley frequency parameter has small values. Using an integral transform method, analytical solutions for any values of the Womersley parameter are *** simulations are performed using mATHCAD to study the influence of stenosis and magnetic field on the flow parameters. When entering the stenosed area, blood velocity increases slightly, but increases considerably and reaches its maximum value in the stenosis throat. it is concluded that the magnitude of axial velocity varies considerably when the applied magnetic field is strong. The magnitude of maximum fluid velocity is high in the case of weak magnetic fields. This is due to the Lorentz's force that opposes motion of an electrically conducting fluid. The effect of externally transverse magnetic field is to decelerate the flow of blood. The shear stress consistently decreases in the presence of a magnetic field with increasing intensity.

关键词： Bingham plastic fluid, magnetic particle, blood flow, magnetohydrodynam-ics, artery stenosis

Effect of coaxial laser cladding parameters on bead formation

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international Journal of minerals,metallurgy and materials 2017年第5期24卷 550-556页

作者： A.i.Noskov A.Kh.Gilmutdinov R.m.Yanbaev Kazan National Research Technical University 10 Karl Marx Str. Kazan 420111 Republic of Tatarstan Russian Federation

We investigated the shape and morphology of nickel-based powder particles (Sulzer metco) and coatings produced by laser gas-powder deposition onto steel substrates. Laser deposition was performed using an LC-10 iPG-Photonics laser complex equipped with a 10-kW fiber laser. The shape and microstructure of the samples were studied using optical and electronic microscopy and X-ray diffraction analysis. The results showed that the deposition speed and laser power significantly influenced the shape and size of the beads. The depth of diffusion of nickel into the steel substrate after deposition was less than 20 μm; the microstructure of the resulting coating was fcc Fe3Ni. As a result, detailed information about the form and shape of the filler powder, modes of its deposition, and the resulting coating structure was obtained; this information is important for the production of high-quality products by additive technologies.

关键词： laser cladding additive manufacturing microstructure morphology bead formation

Epistasis and maternal Effect in Resistance to Puccinia coronata ***. avenae Eriks in Oats(Avena sp.)

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Agricultural Sciences in China 2010年第10期9卷 1462-1466页

作者： Bnejdi F Hammami i Allagui m B Saadoun m el Gazzah m Laboratoire de Génétique et Biométrie Faculté des Sciences de Tunis Université Tunis institut National de la Recherche Agronomique de Tunisie(iNRAT) Rue Hadi Karray

The objective of this paper was to investigate the mode of heredity for resistance in oats （Avena sp.） to crown rust caused by Puccinia coronata Cda. f. sp. avenae Eriks, Eight generations of 2 crosses were used to estimate genetic effects and narrow-sense heritability （NSH）. Separate generation means analysis （GmA） indicated a complex gene action controlling this trait with additive, dominance, epistatic and maternal effects （mE）. The genetic model which assumed no epistasis and no mE did not accurately describe the resistance to P. coronata. in both crosses, the digenic epistatic model with mE was sufficient to explain variation in generation means for isolate CRec58 and isolate CRec46. Additive dominance and epistatic components were negative in most cases, suggesting that gene effects contributed more to the resistance than to the susceptibility. The estimated values of NSH were 15-99% depending upon the cross and isolates. The results indicated that appropriate choice of maternal parent and recurrent selection would increase resistance to crown rust in oats.

关键词： epistasis heritability maternal effect resistance

A scale-integrated exploration model for orogenic gold deposits based on a mineral system approach

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Geoscience Frontiers 2020年第3期11卷 719-738页

作者： David i.Groves m.Santosh Liang Zhang Orebusters Pty Ltd Gwelup6018WAAustralia State Key Laboratory of Geological Processes and mineral Resources China University of Geosciences(Beijing)Beijing100083China Dept.of Earth Sciences University of AdelaideSA5005Australia Yonsei Frontier Lab Yonsei UniversitySeoul120-749Republic of Korea

Concept-based orogenic gold exploration requires a scale-integrated approach using a robust mineral system *** genetic hypotheses for orogenic gold deposits that involve near-surface or magmatic-hydrothermal fluids are now negated in terms of a global mineral system *** models involve metamorphic fluids,but the fluid source has been *** metamorphic-fluid models are most widely-accepted but there are serious problems for Archean deposits,and numerous Chinese provinces,including Jiaodong,where the only feasible fluid source is *** all orogenic gold deposits define a coherent mineral system,there are only two realistic sources of fluid and gold,based on their syn-mineralization geodynamic *** are from devolatilization of a subducted oceanic slab with its overlying gold-bearing sulfide-rich sedimentary package,or release from mantle lithosphere that was metasomatized and fertilized during a subduction event,particularly adjacent to craton *** this model,CO_2 is generated during decarbonation and S and ore-related elements released from transformation of pyrite to pyrrhotite at about 500 ℃.This orogenic gold mineral system can be applied to conceptual exploration by first identifying the required settings at geodynamic to deposit *** these settings,it is then possible to define the critical gold mineralization processes in the system:fertility,architecture,and *** geological parameters that define these processes,and the geological,geophysical and geochemical proxies and responses for these critical parameters can then be *** the geodynamic to province scales,critical processes include a tectonic thermal engine and deep,effective,fluid plumbing system driven by seismic swarms up lithosphere-scale faults in an oblique-slip regime during uplift late in the orogenic cycle of a convergent *** the district to deposit scale,the important processes are fluid focussing into regio

关键词： mineral systems Orogenic gold Sub-crustal fluids Convergent margins Gold exploration

A case study of the stability of a non-typical bleeder entry system at a *** mine

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international Journal of mining Science and Technology 2020年第1期30卷 25-31页

作者： T.m.Klemetti m.A.Van Dyke i.B.Tulu D.Tuncay NiOSH Pittsburgh mining Research Division Pittsburgh 15236USA Department of mining Engineering West Virginia UniversityMorgantown 26505USA

Longwall abutment loads are influenced by several factors,including depth of cover,pillar sizes,panel dimensions,geological setting,mining height,proximity to gob,intersection type,and size of the *** does proximity to the gob affect pillar loading and entry condition?Does the gob influence depend on whether the abutment load is a forward,side,or rear loading?Do non-typical bleeder entry systems follow the traditional front and side abutment loading and extent concepts?if not,will an improved understanding of the combined abutment extent warrant a change in pillar design or standing support in bleeder entries?This paper details observations made in the non-typical bleeder entries of a moderate depth longwall panel—specifically,data collected from borehole pressure cells and roof extensometers,observations of the conditions of the entries,and numerical modeling of the bleeder entries during longwall *** primary focus was on the extent and magnitude of the abutment loading experienced due to the extraction of the longwall *** to the layout of the longwall panels and bleeder entries,the borehole pressure cells(BPCs)and roof extensometers did not show much change due to the advancing of the first ***,they did show a noticeable increase due to the second longwall advancement,with a maximum of about 4 mPa of pressure increase and 5mmof roof *** observations of the conditions showed little to no change from before the first longwall panel extraction began to when the second longwall panel had been advanced more than 915 *** pillar spalling was observed on the corners of the pillars closest to the longwall gob as well as an increase in water in the *** addition to the observations and instrumentation,numerical modeling was performed to validate modeling procedures against the monitoring results and evaluate the bleeder *** Consulting Group’s FLAC3D numerical modeling software was used to evaluate the bl

关键词： Abutment loading Longwall instrumentation Bore hole pressure cells Pillar loading Yield pillar Bleeder pillar

Control of animal brucellosis: the malaysian experience

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Asian Pacific Journal of Tropical medicine 2016年第12期9卷 1111-1115页

作者： m.Zamri-Saad m.i.Kamarudin Research Centre for Ruminant Diseases Faculty of Veterinary MedicineUniversiti Putra Malaysia Department of Veterinary Services malaysia Ministry of Agriculture and Agro-based Industry

Brucellosis is a zoonotic disease characterized by reproductive failure in animals and undulent fever in humans. in cattle, it is caused by Brucella abortus while in goats by Brucella melitensis, the main cause of brucellosis in humans. Brucellosis in livestock has been associated with importation of animals from breeder herd of unknown disease status. The prevalence of bovine brucellosis Brucella abortus in 2014 ranged between 1%-2% in Thailand and indonesia, and 4%-5% in malaysia and myanmar. Prevalence of goat brucellosis Brucella melitensis is approximately 1% in malaysia and Thailand. ‘Test-and-slaughter' is the general policy against brucellosis adopted by most ASEAN countries to eradicate the disease. Under this program, the Rose Bengal Plate Test(RBPT) is used as the screening test to identify infected farm/herd while the Complement Fixation Test(CFT) is the confirmatory test. The test-and-slaughter eradication strategy that was implemented since 1979 had managed to keep the prevalence rate to less than 5%, from 3.3% in 1979, 0.23% in 1988, 1% in 1998 and 5% in 2016. The test-and-slaughter program seemed effective in reducing the prevalence of brucellosis but was unable to eradicate the disease due to several factors, which include failure to locate and identify the remaining affected animals and to control their movement, importation of breeder animals from non-brucellosis free countries and lack of participation by the farmers following unrealiable test results. To support the eradication policy, research activities since 1980 s have suggested combinations of serological tests to improve diagnosis while surveillance should be focused on hotspots areas. The prevalence can be further reduced by strictly sourcing breeder animals from brucella-free areas or countries.

关键词： Brucellosis Animal Control

Coherence of SH-waves near a semi-circular inclusion-the role of interference and standing waves

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Earthquake Engineering and Engineering Vibration 2021年第3期20卷 535-552页

作者： Z.Tokmechi R.S.Jalali m.D.Trifunac m.i.Todorovska Department of Civil Engineering Faculty of EngineeringUniversity of GuilanP.O.Box 3756RashtIran Department of Civil Engineering University of Southern CaliforniaLos AngelesCalifornia 90089USA Department of Civil Engineering Tianjin UniversityTianjin 300350China

We present examples of a controlled numerical experiment that contribute towards understanding of the physical phenomena that lead to the reduction of coherency of strong earthquake ground *** show examples for separation distance of 100 m between the two points on the ground surface,which is in the range of engineering *** examples illustrate the consequences of:(a)standing waves that result from interference of the incident and reflected waves from a near vertical contrast in material properties,(b)standing waves within a concave inhomogeneity(a semi-circular valley in our examples),and(c)smaller motions in the diffraction zone,behind the *** show that it is possible to reduce coherency,to the extent observed for recorded strong earthquake ground motion,even by a single inclusion in a half space,for incident ground motion that is *** also illustrate the combined effects of geometric spreading and finite fault width,superimposed on the otherwise dominating effects caused by *** examples show reduction of coherence for specific angles of incident waves,while,for other angles of incidence,the coherence remains essentially equal to one.

关键词： coherence of strong motion coherence in the presence of standing waves coherence caused by interference reduction of coherence for radiation from large faults